1. Field of the Invention
This invention relates to annular hole cutters. Class 408, Cutting by Use of Rotating Axially Moving Tool, Subclass 204, United States Patent Office Classification, appears to be the applicable general area of art to which the subject matter similar to this invention has been classified in the past.
2. Description of the Prior Art
Portable magnetic drill presses are used on construction projects for drilling holes in metal construction members, and they have a major limitation in the variance of their revolutions per minute. Experience has shown that when the motors of such magnetic drill presses are required to drive or rotate large diameter annular hole cutters that their revolutions per minute are too fast for such large diameter annular hole cutters to effectively and efficiently enter a workpiece. Under such conditions a large diameter annular cutter chatters or vibrates to a point where it is very difficult to start an initial cut in a workpiece. The chattering and vibration in some cases becomes so violent that a large diameter annular hole cutter becomes damaged. The annular hole cutter of the present invention, with its staggered cutting teeth, is configured for large diameter annular hole cutters which are capable of entering into a workpiece with no vibration.